Silicone containing polymeric materials

ABSTRACT

A polymeric material with a variable modulus of elasticity is described herein. The polymeric material described herein is useful for forming implantable medical devices (e.g. ophthalmic lenses, breast implants, and body augmentation devices). In addition, medical devices formed from the polymer material can be used to controllably release a therapeutic agent. Also, the polymeric material may be used to prepare topical compositions or other applications or devices where control of a mechanical property such as material modulus is important.

FIELD OF THE INVENTION

Disclosed herein are polymeric materials having an average of more thantwo terminal vinyl groups.

BACKGROUND OF THE INVENTION

The use of polymeric materials for medical devices is an area where vastimprovements in polymeric materials have evolved and are still evolving.Physical properties of these polymers can be fine tuned for use indifferent environments or to behave in a predictable manner. Polymersfor use in fabricating IOLs need to be adapted allowing for smallerincisions during implantation.

In addition to polymers with physical properties adapted for use in theoptic region, polymeric material can be adapted for various applicationselsewhere. Various medical devices other than optic implants canincorporate elastomeric polymeric material, for example, implantablemedical device coatings, breast implants, prosthetic joins and otherbody augmentation implants. These types of applications each requirepolymeric material that may be vastly different from another. Theability of a skilled artisan is necessary to fine tune the physicalproperties of the polymers.

In addition to medical devices and medical device coatings, polymericmaterial can be incorporated into topical formulations. A low degree ofpolymerization can be used, for example, to form a more liquid polymericmaterial which can be useful in such formulations as eye drops or hairsprays. Increasing the degree of polymerization can cause the polymer tobecome more viscous wherein the polymer may be useful in skin creams orlotions. The degree of polymerization can be tailored for theappropriate application and various other variations are possible.

In the area of ophthalmic devices, IOLs have been designed for eversmaller incisions in the eye. Elastomeric IOLs are typically implantedusing inserters to roll or fold the IOL, insert the IOL into thecapsular sac, and then allow the IOL to unfold once inside.Occasionally, the fold of the IOL before insertion may result inpermanent deformation, which adversely affected the implant's opticalqualities. Further, while foldable IOLs have eliminated the need for thelarge incision, foldable IOLs are not without drawbacks. In particular,both non-deformable and foldable IOLs are susceptible to mechanicaldislocation resulting in damage to the corneal endothelium.

Another approach to small incision IOL implantation uses an elastomericpolymer that becomes pliable when heated to body temperature or slightlyabove. Specifically, the IOL is made pliable and is deformed along atleast one axis, reducing its size for subsequent insertion through asmall incision. The IOL is then cooled to retain the modified shape. Thecooled IOL is inserted into the capsular sac and the natural bodytemperature warms the IOL at which point it returns to its originalshape. The primary drawback to this type of thermoplastic IOL is thelimited number of polymers that meet the exacting needs of thisapproach. Most polymers are composed of polymethylacyrlate which havesolid-elastomeric transition temperatures above 100° C. Modifications ofthe polymer substrate require the use of plasticizers that mayeventually leach into the eye causing harmful effects.

Dehydrated hydrogels have also been used with small incision techniques.Hydrogel IOLs are dehydrated before insertion and naturally rehydratedonce inside the capsular sac. However, once fully rehydrated the polymerstructure is notoriously weak due to the large amount of water absorbed.The typical dehydrated hydrogel's diameter will expand from 3 mm to 6 mmresulting in an IOL that is 85% water. At this water concentration therefractive index (RI) drops to about 1.36, which is unacceptable for anIOL since lower RI materials require the optic to be thicker to achievea given optical power.

Modern acrylate IOLs generally possess excellent mechanical propertiessuch as foldability, tear resistance and physical strength. AcrylateIOLs also are known to possess desriable optical properties(transparency, high refractive index, etc.) and biocompatibility. Whilepure acrylic IOLs have desirable mechanical, optical and biologicalproperties, they may have unacceptable molecular response times suchthat the folded or compacted IOL may not unfold as quickly as desired. Apure acrylate IOL fabricated to have a relatively fast molecularresponse time may be extremely tacky and lack the desired mechanicalstrength. In this case, the resulting IOL may tear and/or the resultingself-tack can unfolding difficult.

Pure silicone IOLs generally possess excellent mechanical, optical andbiological properties similar to pure acrylate IOLs. Unlike acrylicIOLs, silicone IOLs generally possess faster molecular response times.In fact, the silicone IOLs may be so responsive that when folded smallenough to be inserted through a 3 mm or smaller incision, the storedenergy can cause the IOL to unfold more quickly than desired.

There is a need for a polymeric material with a molecular response timewhich makes it suitable for use near fragile body tissues, such aswithin the eye of a subject. There is also a need for ophthalmic devicesin which one polymeric material is useful for both low modulus and highmodulus elements of a single device to, inter alia, simplify themulti-part polymeric article manufacturing process and create betterintegrated multi-part polymeric articles in which the various elementsof the device have a common value of a property such as a refractiveindex, but a different value of another property such as modulus,tensile strength, resiliency, or the like.

SUMMARY OF THE INVENTION

The problems associated with previous polymer materials are solved byproviding materials that have an average of more than two vinylterminations. Moduli may be selected by adjusting hydride to vinylratio, varying the number of vinyl terminations on the silicone fluid,varying the number of vinyl pendent groups on the silicone fluids,and/or the amount of catalyst. Low modulus polymers prepared asdescribed herein also are ideal starting materials for many productsimplantable in patients (e.g., IOLs, augmentation implants). Inaddition, polymers with capable of different degrees of polymerizationare described. Polymers with a low degree of polymerization can beuseful for pharmaceutical compositions (eg. contact lens solutions),while polymers with a medium degree of polymerization can be useful fortopical compositions (eg. hairspray, skin lotions, skin creams) aredescribed. Polymers as described herein can also be used to controllablyrelease a bioactive agent. Embodiments of the present invention may alsobe utilized in other applications where control of a mechanical propertysuch as material modulus is important.

In one embodiment, a polymer comprising a plurality of monomers has ageneral structure of formula 1,

wherein the sum of m and n is x, x ranges from 0 to about 12000, yranges from 0 to about 500, and z ranges from 0 to about 500, the sum ofx, y, and z is at least 1, R¹-R⁸ are each independently CH₃, C₆H₅ orCH═CH₂, if m is greater than zero, at least one of R⁴ or R⁵ is CH═CH₂,and wherein more than two of R¹, R², R³, R⁶, R⁷, or R⁸ are CH═CH₂. Inanother embodiment, the monomers comprise at least one pendent vinylgroup. In another embodiment, the monomers comprise an average of 3 ormore vinyl terminations. In another embodiment, the polymer is capableof controlled release of an active agent.

In one embodiment, the polymer has a general structure of formula 2.

wherein the sum of m and n is x, x ranges from 0 to about 12000, yranges from 0 to about 500, and z ranges from 0 to about 500, the sum ofx, y, and z is at least 1, if m is greater than zero, and at least oneof R⁴ or R⁵ must be CH═CH₂.

In one embodiment, an ocular lens is described which comprises a polymerhaving a general structure of formula 1,

wherein the sum of m and n is x, x ranges from 0 to about 12000, yranges from 0 to about 500, and z ranges from 0 to about 500, the sum ofx, y, and z is at least 1, R¹-R⁸ are each independently CH₃, C₆H₅ orCH═CH₂, if m is greater than zero, at least one of R⁴ or R⁵ must beCH═CH₂, and wherein more than two of R¹, R², R³, R⁶, R⁷, or R⁸ areCH═CH₂. Herein, the polymer can comprise at least one pendent vinylgroup. In one embodiment, the polymer is a hexavinyl terminated siliconefluid.

In one embodiment, the ocular lens is selected from the group consistingof an intraocular lens, a corneal implant, and a contact lens. Inanother embodiment, the intraocular lens comprises an optic and at leastone haptic. In another embodiment, the ocular lens is capable ofcontrolled release of a therapeutic agent.

In one embodiment, the intraocular lens comprises a first portion and asecond portion; wherein the first portion and the second portion have adifferent modulus of elasticity; and wherein the first portion and thesecond portion have the same or about the same refractive index at apredetermined wavelength in the visible light waveband. In anotherembodiment, the intraocular lens comprises an optic, wherein the firstportion comprises an inner portion of the optic and the second portioncomprises an outer portion of the optic dispersed about the innerportion, the portions having same or about the same refractive index ata predetermined wavelength in the visible wavelength band.

In one embodiment, an implantable medical device is described whereinthe implantable medical device is made from a polymer comprising aplurality of monomers and has a general structure of formula 1,

wherein the sum of m and n is x, x ranges from 0 to about 12000, yranges from 0 to about 500, and z ranges from 0 to about 500, the sum ofx, y, and z is at least 1, R¹-R⁸ are each independently CH₃, C₆H₅ orCH═CH₂, if m is greater than zero, at least one of R⁴ or R⁵ must beCH═CH₂, and wherein more than two of R¹, R², R³, R⁶, R⁷, or R⁸ areCH═CH₂.

In one embodiment, the monomers comprise an average of three or morevinyl terminations. Herein in some embodiments, the monomers cancomprise six vinyl terminations. In another embodiment, the implantablemedical device is selected from the group consisting of bodyaugmentation implants, breast implants, ocular lenses, and intraocularlenses, further wherein said implantable medical device is capable ofcontrolled release of a therapeutic agent.

In one embodiment, a method of forming an elastomeric article ofmanufacture comprises (a) providing polymers comprising a plurality ofmonomers and having the general structure of formula 1,

wherein the sum of m and n is x, x ranges from 0 to about 12000, yranges from 0 to about 500, and z ranges from 0 to about 500, the sum ofx, y, and z is at least 1, R¹-R⁸ are each independently CH₃, C₆H₅ orCH═CH₂, if m is greater than zero, at least one of R⁴ or R⁵ must beCH═CH₂, and wherein more than two of R¹, R², R³, R⁶, R⁷, or R⁸ areCH═CH₂, (b) providing a cross-linker, (c) providing a catalyst, (d)combining said monomers, said cross-linker and said catalyst to form apolymeric mixture and (e) curing said polymeric mixture, wherein atleast a portion of said article of manufacture is formed. In anotherembodiment, the article of manufacture is selected from the groupconsisting of intraocular lenses, corneal implants, contact lenses,ocular lenses, body augmentation implants, medical device coatings, andbreast implants. In another embodiment, the article of manufacture iscapable of controlled release of a therapeutic agent.

In one embodiment, a topical composition comprising polymers having thegeneral structure formula:

wherein the sum of m and n is x, x ranges from 0 to about 12000, yranges from 0 to about 500, and z ranges from 0 to about 500, the sum ofx, y, and z is at least 1, R¹-R⁸ are each independently CH₃, C₅H₅ orCH═CH₂, if m is greater than zero, at least one of R⁴ or R⁵ must beCH═CH₂, and wherein more than two of R¹, R², R³, R⁶, R⁷, or R⁸ areCH═CH₂. In another embodiment, the topical composition is selected fromthe group consisting of skin creams, sprays, and lotions. In anotherembodiment, the topical composition is capable of absorbing UV light. Inyet another embodiment, the polymer of the topical composition iscapable of controlled release of a therapeutic agent.

Definition of Terms

The terms and phrases used herein shall have the following,non-limiting, definitions.

Elongation: As used herein, “elongation” refers to the act oflengthening or stretching a polymeric material. In some instances, theelongation may be represented by the following formula where L is thelength of the elongated polymer and L₀ is the length of thecorresponding non-elongated polymer: [L/L₀]

Full Elongation: As used herein, “full elongation” refers to the act oflengthening or stretching a polymeric material or polymeric IOL to itselastic limit.

Intermediate Elongation: As used herein, “intermediate elongation”refers to the act of lengthening or stretching a polymeric material orpolymeric IOL to a point between its original length and limit.

Glass Transition Temperature (T_(g)): As used herein, the “glasstransition temperature (T_(g))” refers to the temperature wherein apolymeric material becomes less elastic and more brittle. For softpolymeric materials, T_(g) typically is not measured since it may be aslow as −100° C. or lower.

Mass percent: As used herein, “mass percent” and “mass %” refer to themass of monomer present in a polymer divided by the total weight of thepolymer multiplied by 100. Mathematically, mass percent is representedby the following formula where M_(m) is the mass of the monomer andM_(P) is the mass of the corresponding polymer: [M_(m)/M_(P)]×100=MassPercent.

Compression Modulus or Modulus of Elasticity: As used herein “modulus ofelasticity” refers to the ratio of stress to strain. As used herein,“compression modulus” refers to the ratio of compressive stress tocompressive strain.

Moduli: As used herein, “moduli” refers to the plural form of modulus ormodulus of elasticity.

Percent Elongation: As used herein, “percent elongation” refers to thelength of an elongated polymer divided by the length of the originalpolymer. Mathematically, the percent elongation is represented by thefollowing formula where L is the length of the elongated polymer and L₀is the length of the corresponding non-elongated polymer:[L/L₀]×100=Percent Elongation.

Pliable: As used herein, “pliable” refers to the flexible nature of apolymeric material and to the flexibility of polymeric IOLs that can befolded, rolled or otherwise deformed sufficiently to be inserted througha 2 mm or less surgical incision.

kPa: As used herein, “kPa” refers to kilopascal, which is a unit ofpressure or stress and is the equal to 1000×Newton per meter squared(N/m²).

Resiliency: As used herein, “resiliency” refers to a polymericmaterial's or a polymeric IOL's inherent ability to return to itsunstressed configuration following impact, deformation in an inserter,or the resulting deformation associated with the stress on impact, alsoreferred to herein after as “rebound resiliency.”

Refractive Index (RI): As used herein, “refractive index (RI)” refers toa measurement of the refraction of light of a material or object, suchas an IOL. More specifically, it is a measurement of the ratio of thespeed of light in a vacuum or reference medium to the speed of light inthe medium of a substance, material, or device under examination. Therefractive index of a substance, material, or device typically varieswith the wavelength of the light, a phenomenon sometimes referred to asdispersion.

Softness: As used herein, “softness” refers to a polymeric material's ora polymeric IOL's pliability as opposed to, for example, apolymethylmethacrylate (PMMA) IOL that is rigid and hard.

Ultimate Tensile Strength: As used herein, “ultimate tensile strength”refers to the maximum stress a material can withstand before fractureand is measured in psi (lb/in²).

Clear Aperture: As used herein, “clear aperture” refers to the portionof an optic that limits the extent of the rays from an object thatcontributes to the conjugate image and is generally expressed as adiameter of a circle.

Common Polymeric Material: As used herein, “common polymeric material”refers to similarity of material composition between two objects orportions of an object. Two objects or portions of an object comprise acommon polymeric material if the two objects or portions consistessentially of the same base polymer chain or have at least 50% w/w ofthe same base polymer chain, or 75% w/w of the same base polymer chain,or 85% w/w of the same base polymer chain, or 90% w/w of the same basepolymer chain, or 95% w/w of the same base polymer chain, and, whenpresent, the same cross-linking agent.

Common Refractive Index: As used herein, “common refractive index”refers to the similarity of refractive indices between two materials. Acommon refractive index between two materials would be a difference inrefractive index between the two materials of less than or equal to 1%at a predetermined wavelength in the visible light waveband.

DETAILED DESCRIPTION

Embodiments of the present invention may include polymer materials andcompositions with moduli that may be altered based, for example, onhydride to vinyl ratio, amount of catalyst, varying the number of vinylterminations on the silicone fluid, varying the number of pendent vinylgroups on the silicone fluid, and/or MVC content are described herein.Also, low modulus materials are included that exhibit mechanicalqualities that make them excellent for implantation in living organisms,particularly animals, more particularly humans. In some embodiment, alow modulus material is used to provide devices including, but notlimited to, ophthalmic lenses such as IOLs or contact lenses, breast orother augmentative implants, and controlled release devices (e.g.,pharmaceutical formulations). The mechanical qualities and feel of suchlow modulus materials make it possible to prepare bodily augmentationdevices that are implantable in a living organism, for example, breastimplants containing little or no liquid. In addition, polymers withdifferent degrees of polymerization are anticipated. In certainembodiments, polymers with a low degree of polymerization are used toprovide pharmaceutical compositions (e.g., contact lens solutions). Inother embodiments, polymers with a medium degree of polymerization areused to provide topical compositions (e.g., hairspray, skin lotions,skin creams). Polymers as described herein can also be used tocontrollably release a bioactive agent. Embodiments of the presentinvention may also be utilized in other applications or devices wherecontrol of a mechanical property such as material modulus is important.

As for IOLs, it is desirable they can be folded, rolled or otherwisedeformed such that they can be inserted through small incisions.Furthermore, in order to reduce patient trauma and post surgicalrecovery time, the IOL preferably comprises a responsive polymer thatunfolds in a controlled manner. To meet these requirements, the polymerspreferably have minimal self tack and do not retain excessive amounts ofstored mechanical energy.

Historically, foldable IOL materials have been designed to be tough(tensile strength of greater than 750 pounds per square inch [psi]) andwith a relatively high percent elongation (greater than 100%). Theseproperties give the IOL sufficient toughness such that the IOL does nottear from the forces experienced during insertion through a 2.6 to 3.2mm incision. Presently available foldable IOLs include, among others,Sensar® (Advanced Medical Optics, Santa Ana Calif.), an acrylic IOLhaving a tensile strength of about 850 psi and an elongation at break ofabout 140%; SLM-2® (Advanced Medical Optics, Santa Ana Calif.), asilicone IOL having a tensile strength of about 800 psi and anelongation at break of about 230%; and AcrySof® (Alcon Laboratories,Fort Worth, Tex.) having a tensile strength of about 1050 psi. Such IOLsare suitable for insertion through incision sizes of about 2.6 mm orgreater.

The polymer materials described herein may be used to form may be usedto form ophthalmic devices and other devices that are soft to very softand may be foldable.

Flexibility in monomer selection is provided herein, which provides forcontrol over the material's mechanical, optical and/or thermalproperties. For example, the ability to adjust a material's refractiveindex (RI) and mechanical properties is important in designingultra-small incision IOLs. Also, hydrophobic siloxy materials havingexcellent ocular biocompatibility are anticipated. Thus, it surprisinglyhas been discovered that by utilizing the silicone materials accordingto embodiments of the present invention an IOL optic can be made thathas properties permitting passage of the IOL through an ultra smallincision without damage to the IOL, the inserter cartridge, or the eye.In addition, the IOL may have at least one resilient haptic that sharesa common siloxy monomer with the optic.

In certain embodiment, silicone materials having unique properties arederived from the inherent flexibility of the siloxane bond. Thealternating silicon-oxygen polymer backbone of siloxanes may make themremarkably more flexible than their organic counterparts that have acarbon-oxygen backbone. This property of siloxanes results in lowglass-transition temperatures (T_(g)) and excellent flexibility.Furthermore, a low initial modulus is another important attribute of thenovel siloxanes. In order to pass through the insertion cartridge, arefractive IOL is desirably capable of elongating up to about 100%.Therefore, it may be important that the initial modulus is at desirablelevels. A low initial modulus translates to low stimulus required toexpress the IOL through the cartridge. Further, when a desired amount ofselected siloxanes, cross linkers and catalysts are combined, theresulting material may have the flexibility and modulus required tomake, for example, the optic portion of an IOL suitable for insertionthrough a small incision without harming the IOL, the insertercartridge, or the eye.

In some embodiments, an intraocular lens comprises an optic and a hapticmade from a common polymeric material so that they also have a commonrefractive index; however, the optic and haptic have mechanical propertythat is different for each. In some embodiments, the IOL may be formedaccording to an embodiment so that the optic and haptic have differentmoduli of elasticity. For example, an accommodating IOL may be formed sothat the optic has a lower modulus than the haptic, thus allowing therelatively stiff haptic to protrude inside the relatively soft opticwithout causing unwanted reflections due to a refractive index mismatchat interfaces between the optic and the protruding haptic. Examples ofaccommodating IOLs having a stiffer protruding haptic are disclosed inco-pending U.S. patent application Ser. Nos. 11/618,411, 11/618,325, and11/864,450, which are herein incorporated by reference in their entiretyOne way to adjust moduli between the haptic and optic may be provided byan adjustment in the amount of cross-linker and/or catalyst and/or MVCcontent of each IOL component. Embodiments herein may be used to provideIOL's in which at least the optic thereof has a modulus that is lessthan about 100 kPa, less than 75 kPa, or even less than 50 kPa or 25kPa. The stiffness of the haptic may be greater than 500 kPa, or greaterthan 3000 kPa, depending on the particular design requirements. In someembodiments, the modulus of the haptic is greater than that of the opticby at least 50%, by at least 150%, by at least 250%, or by at least500%. In some embodiments, the modulus may vary continuously over atleast some interface regions between the haptic and the optic, forexample, to provide a particular performance or stress distribution overthe IOL in reaction to an external force on the IOL (e.g., an ocularforce produced by the capsular bag, zonules, or ciliary muscle of an eyeinto which the IOL is inserted).

In some embodiments, an ophthalmic lens, such as an intraocular lens,comprises an optic having a clear aperture that comprises an innerportion and an outer portion disposed about said inner portion. Theinner portion and outer portion comprise a common polymeric material andmay have a common refraction index; however, the inner portion has amodulus that is different from that of the outer portion. The differencein modulus may be selected, for example, to control the amount and/orform of deformation of the optic in reaction to an external force suchas an ocular force produced by the capsular bag, the zonules, and/or theciliary muscle of an eye into which the optic is placed. In someembodiments, the refractive index may also vary between the zones, forexample, to control aberrations of the optic in a stressed or unstressedstate.

The modulus of the inner portion of the optic may by greater than orless than that of the outer portion, depending of the particular designrequirements. In some embodiments, the optic comprises three or morezones disposed within the clear aperture of the optic. In otherembodiments, the modulus of at least portions of the optic may varycontinually, for example, by producing a catalyst gradient throughout apolymeric fluid used to form the optic. In some embodiments, the zonesof the optic may have an ellipsoid or similar shape, such that themodulus varies from the center of the optic outward in athree-dimensional manner. Alternatively or additionally, the variationin modulus of the zones may vary in a two dimensional manner, forexample, forming concentric rings as the modulus varies in radialdirection from the optical axis of the optic. The difference in modulusbetween two zones of the optic may be greater than or equal to 5%, orgreater than or equal to 15%, or greater than or equal to 25%, orgreater than or equal to 50%, depending on the number of zones and thedesired performance of the optic under a given loading force.

Some embodiments may provide a relatively low modulus material that isparticularly suitable for use in at least the optic of an accommodatingIOL. For example, an adjustment in the amount of cross-linker, number ofvinyl terminations, number of vinyl pendent groups, catalyst and/or MVCcontent, the haptic portion of an IOL or accommodating IOL may be made.Embodiments may be used to provide IOL's in which at least the opticthereof has a modulus that is less than about 100 kPa, less than 75 kPa,or even less than 50 kPa or 25 kPa.

The materials made may have low initial moduli and a low glasstransition temperature (T_(g)). Moreover, the IOLs may be multifocal(either refractive or diffractive), accommodating (e.g., deformable ormovable under the normal muscle movements of the human eye), highlybiocompatible and have RIs ranging from about 1.40 to about 1.56,preferably from about 1.41 to about 1.52, for light in the visiblewavelengths. These and other objects described herein may be achieved byproviding an unsaturated terminated silicone fluid and cross-linking itusing a hydride cross-linking agent and platinum catalyst. Theunsaturated terminated silicone fluid, in some embodiments, can havemore than three vinyl terminations. In different embodiments, theunsaturated terminated silicone fluid can have three, four, five or sixvinyl terminations. In another embodiment, metals aside from platinum,more preferably transition metals, may be used. Herein, silicone fluidsare disclosed that may be cross-linked to prepare polymers withdifferent moduli.

The unsaturated terminated siloxanes are preferably vinyl terminatedsiloxanes, more preferably multi-vinyl terminated. Non-limiting examplesinclude vinyl terminated diphenylsiloxane-dimethylsiloxane copolymers,vinyl terminated polyphenylmethylsiloxanes, vinyl terminatedphenylmethylsiloxane-diphenyidimethylsiloxane copolymers, vinylterminated polydimethylsiloxanes and methacrylate, and acrylatefunctional siloxanes. Other suitable silicone materials are disclosed inU.S. Pat. No. 6,361,561, the entirety of which is incorporated herein byreference. Representative materials can be obtained from Gelest, Inc.(Morrisville, Pa.) or synthesized using methods known to those skilledin the art.

In one embodiment, the unsaturated terminated siloxane is a vinylterminated siloxane comprising polymers of the structure depicted inFormula 1 below (herein referred to as “silicone fluid”). In otherembodiments, polymers can consist of greater than 50% w/w having thestructure of Formula 1, or greater than 75% w/w having the structure ofFormula 1, or greater than 85% w/w having the structure of Formula 1, orgreater than 90% w/w having the structure of Formula 1, or greater than95% w/w having the structure of Formula 1. The values for x, y, and zwill vary depending on, for example, the desired RI of the lens; and, inFormula 1, x is equal to the sum of m and n and is preferably at leastabout 1. In one embodiment, the sum of x, y, and z is greater than orequal to about 1. Preferably, IOLs produced have an RI of at least 1.40,more preferably at least 1.43. For example, if an IOL having arefractive index (“RI”) of 1.43 is desired, the x:y:z ratio may beapproximately 30:1:1; a x:y:z ratio of about 12:1:2 will result in anIOL having a RI of approximately 1.46. Skilled artisans can prepare anIOL having a desired RI, optical clarity and mechanical properties byadjusting the x:y:z ratio using skills known in the art and withoutundue experimentation. In one embodiment, x ranges from 0 to about12000, y ranges from 0 to about 500, z ranges from 0 to about 500, andthe sum of x, y, and z is greater than or equal to 1. In anotherembodiment, x ranges from about 10 to about 12000, y ranges from about 1to about 500, z ranges from 0 to about 500, and the sum of x, y, and zis from about 100 to about 15000. In another embodiment, x+y+z has aminimum value of about 200 in order to provide a high softness polymer(e.g., when required for optic portions of an IOL). R¹-R⁸ are eachindependently CH₃, C₆H₅ or CH═CH₂. If m is greater than zero, at leastone of R⁴ or R⁵ must be CH═CH₂. In one embodiment, more than two of R¹,R², R³, R⁶, R⁷, and R⁸ are CH═CH₂.

In another embodiment, at least four of R¹, R², R³, R⁶, R⁷, and R⁸ areCH═CH₂. In another embodiment, at least five are CH═CH₂. In yet anotherembodiment, all six of R¹, R²5 R³, R⁶, R⁷, and R⁸ are CH═CH₂. Theutility of more vinyl terminations, as well as vinyl pendent groups, isto provide the polymer with additional ability to crosslink, the abilityto bind molecules it would otherwise not be able to bind and provideadditional sites of chelation.

In one embodiment, the silicone fluid can be hexavinyl terminated,wherein R¹, R², R³, R⁶, R⁷, and R⁸ can be vinyl terminated and can berepresented by formula 2. In other embodiments, polymers can consist ofgreater than 50% w/w having the structure of Formula 2, or greater than75% w/w having the structure of Formula 2, or greater than 85% w/whaving the structure of Formula 2, or greater than 90% w/w having thestructure of Formula 2, or greater than 95% w/w having the structure ofFormula 2. The values for x, y, and z will vary depending on, forexample, the desired RI of the lens; and, in Formula 3, x is equal tothe sum of m and n. In one embodiment, the sum of x, y, and z is greaterthan or equal to about 1. Preferably, IOLs produced have an RI of atleast 1.40, more preferably at least 1.43. For example, if an IOL havinga refractive index (“RI”) of 1.43 is desired, the x:y:z ratio may beapproximately 30:1:1; a x:y:z ratio of about 12:1:2 will result in anIOL having a RI of approximately 1.46. Skilled artisans can prepare anIOL having a desired RI, optical clarity and mechanical properties byadjusting the x:y:z ratio using skills known in the art and withoutundue experimentation. In one embodiment, x ranges from 0 to about12000, y ranges from 0 to about 500, z ranges from 0 to about 500, andthe sum of x, y, and z is greater than or equal to 1. In anotherembodiment, x ranges from about 10 to about 1200, y ranges from about 1to about 500, z ranges from 0 to about 500, and the sum of x, y, and zis from about 100 to about 2200. In another embodiment, x+y+z has aminimum value of about 200 in order to provide a high softness polymer(e.g., when required for optic portions of an IOL). If m is greater thanzero, at least one of R⁴ or R⁵ must be CH═CH₂.

Combinations for the sum of x+y+z exist for sums from at least 1 toabout 15000. In addition, the sum can determine what type of material isformed. In one embodiment, for example, the sum can be less than about100, in which case, the material can be a liquid and can be used as aliquid carrier formulation, for example, eye drops or hair spray. Inanother embodiment, the sum can be from about 100 to about 1000, whereinthe material can be a more viscous liquid or gel. In one embodiment, thematerial can be used in topical compositions, for example, skin creamsand lotions. In one embodiment, the skin cream can absorb harmful light.In another embodiment, the sum can be from about 300 to about 1200,wherein the material can be formed as an elastomeric. In such anembodiment, the materials formed as elastomerics can be used to formsuch items as lenses. Each of the embodiments described above can beused with other appropriate additives with or without furthercross-linking reactions.

Optionally, a number of ultraviolet (UV) and blue light absorbing dyescan be added to the silicone polymers. For example, the silicone IOLsmay include 0.1 to 1.5 mass % of UV and blue light absorbing compoundssuch as benzophenone and benzotriazole-based UV light absorbers or bluelight blocking dyes including azo and methine yellow, which selectivelyabsorb UV/blue light radiation up to about 450λ. See, for example, U.S.Pat. Nos. 5,374,663; 5,528,322; 5,543,504; 5,662,707; 6,277,940;6,310,215 and 6,326,448, the entire contents of which are incorporatedherein by reference.

A variety of initiators for polymerization reactions can be employed. Inone non-limiting embodiment, peroxide initiators are used. Examples ofperoxide initiators include, without limitation, about 0.100 to about1.50 mass % of di-tert-butyl peroxide (Trigonox® a registered trademarkof Akzo Chemie Nederland B.V. Corporation Amersfoort, Netherlands) or2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy) hexane. It should be notedthat peroxide initiators initiate the cross-linking of vinyl groups onmonomers (e.g., those on divinyl-terminated silicone monomers). Whilethis can help facilitate the cross-linking of the silicone monomers, atleast some of the hydride groups must still be cross-linked.

One or more monomers may be cross-linked utilizing one or morehydride-containing cross-linkers such as, but not limited to:nonpolymetric X-linkers such as phenyltris(dimethylsiloxy)silane(Formula 3 below), tetrakis(dimethylsiloxy)silane (Formula 4 below),1,1,3,3-tetraisopropyldisiloxane, 1,1,3,3-tetramethyldisiloxane,1,1,4,4-tetramethyldisilethane bis(dimethylsilyl)ethane,1,1,3,3-tetramethyldisilazane; hydride terminated polymeric X-linkerswith different molecular weights such as hydride terminatedpolydimethylsiloxane (DMS-H03, DMS-H11 to DMS-H41), hydride terminatedpolyphenyl-(di-methylhydrosiloxy)siloxane (HDP-111, Formula 5 below,wherein W is about 5 to about 50); hydride terminatedmethylhydrosiloxane-phenylmethylsiloxane copolymer (HPM-502), which arecommercially available from Gelest; nonhydride terminated polymericcross-linkers such as methylhydrogen dimethylsiloxane (XL-103, XL-110,XL-111, XL-112, XL-115), which are commercially available from Nusil;and trimethylsiloxane terminated methylhydrosiloxane-dimethylsiloxanecopolymer (HMS-013, HMS-031, HMS-082, HMS-301), trimethylsilylterminated polymethylhydrosiloxane (HMS-991), which are commerciallyavailable from Gelest. Other cross-linkers such as hydride Q resins mayalso be used to improve the mechanical properties of the gels. Thesoftness of the final gel formulations depends on the relative amount ofcross-linker to vinyl silicone fluid (e.g., H/V [hydride-vinyl] ratio).

Properties of the silicone materials such as modulus, percent weightloss may be changed by varying the ratio of hydride and vinyl contents(H/V ratio) in the silicone fluids. Vinyl content of a silicone fluidmay be determined by, for example, the GPC method, titration, or NMR(nuclear magnetic resonance spectroscopy). By varying the ratio ofhydride primarily from the cross-linker and vinyl primarily from thevinyl silicone fluid, silicone materials with different moduli may beobtained. In certain embodiments, the H/V ratio may be at least about0.1, more preferably at least about 0.5, more preferably about 0.6, morepreferably about 0.7, more preferably about 0.8, more preferably about0.9, more preferably about 1.0, more preferably about 1.1, morepreferably about 1.25, and more preferably at most about 1.5.

In certain embodiments, the modulus of material may be affected by theamount of catalyst and/or methyl-vinyl cyclics (“MVCs”). In certainembodiments, as the amount of catalyst and/or MVCs is increased, themodulus of the material may also increase until a peak modulus isreached. In certain embodiments, after a peak modulus is reached, themodulus may begin to level off or, in some cases, may decrease.

In certain embodiments, the MVC may be any methylvinyl siloxane, whichincludes cyclosiloxane and non-cyclosiloxane classes of materials.Nonlimiting examples of methylvinyl cyclosiloxane classes includetetramethylvinylcyclotetrasiloxane andpentamethylvinylcyclopentasiloxane. Non-cyclosiloxane classes include1,3-tetramethyldisiloxane, divinyltetraphenyidisiloxane,1,5-divinylhexamethyltrisiloxane, and1,5-divinyl-3,3-diphenyltetramethyltrisiloxane. One example of an MVC is1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane. In certainembodiments, the MVC may be present in an amount of at least about 0.01%or at most about 1% by weight. It should be understood that for certainpolymer embodiments described herein, MVCs may partially substitute thecatalyst, augment the catalyst or be used to alter the H/V ratio. TheMVC, in certain embodiments, may have an inversely proportional impacton the moduli of polymers prepared therewith.

In general, platinum-containing catalysts work well. Exemplary platinumcatalyst include platinum-tetravinyltetramethylcyclotetrasiloxanecomplex, platinum carbonyl cyclovinylmethylsiloxane complex, platinumcyclovinylmethylsiloxane complex, platinum octanaldehyde/octanolcomplex. Many different platinum catalysts may be used depending on,inter alia, the desired pot life. Preferably, the platinum catalyst isused in amounts by weight of at least about 0.01%, more preferably atleast about 0.05%, even more preferably at least about 0.1%. Preferably,the platinum catalyst is used in amounts of about 1% or less, morepreferably about 0.75% or less, even more preferably about 0.5% or less,even more preferably about 0.4%, even more preferably about 0.3%, evenmore preferably about 0.2%.

In addition to platinum catalysts, other metal catalysts can be used. Insome embodiments, transition metals can be used as catalysts, morespecifically, palladium and rhodium catalysts can be used. Complexes andsalts of metal catalysts can be used. An example of a transition metalcomplex used as a catalyst is tris(dibutylsulfide) rhodium trichloride.

For certain embodiments and without wishing to be bound by theory, onereason for the impact of some catalysts, especially platinum catalysts,on the modulus may be due to the presence of an inhibitor or stabilizerthat may reduce the hydride/vinyl ratio and/or may prevent completecuring. An example of such an agent may be an MVC such ascyclovinylmethylsiloxane (e.g.,1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane). It isworthwhile to note that in certain embodiments, the effects of catalystamounts on modulus may be independent of curing time. While MVCs maysometimes be used as stabilizers in catalysts to, for example, keepplatinum suspended in solution, the MVCs may be present in such smallamounts that they may be inert.

In certain embodiments, the platinum catalyst level for a polymer may beincreased to levels significantly higher than conventionally used (e.g.,up to 50 ppm versus a more traditional 10 ppm or less). A skilledartisan may expect that as catalyst concentration increases, curing timemay decrease and polymer cross-linking may increase. The skilled artisanmay also expect this to lead to a more rigid or firm polymer (evenassuming curing temperature may be the same). In certain embodiments,the catalyst may be increased to atypical levels and a significantdecrease in curing time may be observed.

In certain embodiments, the resulting polymer may be far less rigid andless firm than expected. In certain embodiments, excessive amounts ofcatalyst may be used and the corresponding increase in MVCs may allowthem to become reactive ingredients and may end-cap the hydrides on thecross-linkers, which may result in more free ends on the structuralpolymers. The additional free ends may provide a less-cross-linked and,therefore, less rigid polymer. As a skilled artisan will appreciate, incertain embodiments, such a polymer may be ideal for preparing manyproducts including, but not limited to, products implantable in patients(e.g., IOLs, augmentation implants).

In certain embodiments, the MVC may be present in an amount of at leastabout 0.01%, about 0.05%, about 0.1%, about 0.11%, about 0.15%, about0.2%, or about 0.25% by weight; to at most about 1%, about 0.75%, about0.5%, about 0.4%, about 0.39%, about 0.35%, or about 0.35% by weight. Incertain embodiments, the MVCs may partially substitute the catalyst inany proportion or amount including completely or the MVC may augment thecatalyst. In certain embodiments, the MVC may have an inverselyproportional impact on the moduli of polymers prepared therewith.Certain embodiments described herein may incorporate the teachingsregarding MVCs and their relationship to the moduli of polymer articlesprepared therefrom.

When used for IOL optic portions, a polymer with a low initial modulusprepared as described herein facilitates a more easily inserted IOL byreducing the force required to express the polymer IOL through aninserter cartridge. In addition, the same starting materials may be usedfor both optic and haptic portions (only varying the H/V ratio and/or %catalyst or, MVC); therefore, the material supply and manufacture ofIOLs is simplified. An added benefit of using the same startingmaterials is that the resulting optic and haptic portions will be morecompatible thereby facilitating more robust and/or seamless fusion.

In another embodiment, the polymers described herein can be used in acomposition for topical administration. An example of a topicalcomposition can be a skin cream, lotion, skin spray, or skin powder. Thepolymers can have double bonded vinyl terminations, wherein the doublebonds can be broken by wavelengths of light. An exemplary, non-limiting,example of wavelengths of light absorbable by the polymers describedherein are wavelengths of light in the UV region. One skilled in the artwill appreciate that UV light can be absorbed by the double bonds. Theabsorption of UV light can generate radicals, for example, but notlimited to, radicals in the form of electrons. The radicals can combineor be reabsorbed by the polymer, or surrounding polymers in thecomposition. The combination and reabsorbing of radicals by the polymercan result in an overall stable composition.

In one embodiment, the polymer may be used as a controlled releasepolymer for formulating therapeutic agents. In addition, the polymer maybe used to prepare dual use implantable or wearable medical devices(e.g., IOLs and contact lenses) whereby the device serves a particularpurpose as well as controllably releasing therapeutic agents. Forexample, the polymer may be used to prepare an IOL that controllablyreleases a therapeutic agent for “dry eye.” A skilled artisan canenvision several devices, conditions, and/or therapeutic agents inconjunction with this embodiment.

Example 1 Preparation of Polymers

A. The following is an example of the synthesis of a hexavinylterminated silicone fluid without pendent vinyl groups. In a method formaking this polymer (polymer B38), 103.48 grams ofoctaphenylcyclotetrasiloxane was placed in a preheated 1000 mL reactionkettle at 105° C. (±10° C.). The mechanical stirrer was turned on andthe system was purged with nitrogen for at least 30 minutes. Next,691.78 grams of octamethylcyclotetrasiloxane and 5.15 grams of hexavinyldislioxane were added together to the reaction kettle. Then, 3.17 gramsof tetramethylammonium siloxanolate was added to the reaction kettle.Stirring continued for at least 68 hours at 105° C. (±10° C.). Thetemperature of the kettle was then raised to 150° C. (±20° C.) for atleast 5 hours. After cooling, the silicone fluid was filtered through a0.2 micron filter.

B. The following is an example of the synthesis of a hexavinylterminated silicone fluid with pendent vinyl groups. In a method formaking this polymer (polymer B37), 129.35 grams ofoctaphenylcyclotetrasiloxane was placed in a preheated 1000 mL reactionkettle at 105° C. (±10° C.). The mechanical stirrer was turned on andthe system was purged with nitrogen for at least 30 minutes. Next,666.32 grams of octamethylcyclotetrasiloxane, 59.72 grams oftetravinyltetramethylcyclotetrasiloxane and 5.53 grams of hexavinyldislioxane were added together to the reaction kettle. Then, 4.54 gramsof tetramethylammonium siloxanolate was added to the reaction kettle.Stirring continued for at least 25 hours at 105° C. (±10° C.0). Thetemperature of the kettle was then raised to 150° C. (±20° C.) for atleast 5 hours. After cooling, the silicone fluid was filtered through a0.2 micron filter.

C. The following is an example of the synthesis of a high refractiveindex hexavinyl terminated silicone fluid. In a method for making thispolymer (polymer B29), 249.63 grams of octaphenylcyclotetrasiloxane wasplaced in a preheated 1000 mL reaction kettle at 105° C. (±10° C.). Themechanical stirrer was turned on and the system was purged with nitrogenfor at least 30 minutes. Next, 546.57 grams ofoctamethylcyclotetrasiloxane and 5.07 grams of hexavinyl dislioxane wereadded together to the reaction kettle. Then, 3.36 grams oftetramethylammonium siloxanolate was added to the reaction kettle.Stirring continued for at least 72 hours at 105° C. (±10° C.). Thetemperature of the kettle was then raised to 150° C. (±20° C.) for atleast 5 hours. After cooling, the silicone fluid was filtered through a0.2 micron filter.

D. The following is an example of the synthesis of a high refractiveindex, high viscosity hexavinyl terminated silicone fluid. In a methodfor making this polymer (polymer B49), 266.48 grams ofoctaphenylcyclotetrasiloxane was placed in a preheated 1000 mL reactionkettle at 105° C. (±10° C.). The mechanical stirrer was turned on andthe system was purged with nitrogen for at least 30 minutes. Next,530.65 grams of octamethylcyclotetrasiloxane and 2.56 grams of hexavinyldislioxane were added together to the reaction kettle. Then, 3.89 gramsof tetramethylammonium siloxanolate was added to the reaction kettle.Stirring continued for at least 18 hours at 105° C. (±11° C.). Thetemperature of the kettle was then raised to 150° C. (±20° C.) for atleast 5 hours. After cooling, the silicone fluid was filtered through a0.2 micron filter.

A Pope 2″ Wiped-Film stills unit was used to remove the volatilecomponents of the above silicone fluids (B38, B37, B29, and B49) bysetting the chiller temperature to 5° C., still body temperature to 160°C., the vacuum range to 0.3-2.0 torr and the rotor speed in the range ofabout 50 to about 70 RPM. A total of about 10% to about 25% of thevolatile components were removed from the silicone fluids.

Next, 0.125 grams of2-(3′-t-butyl-2′-hydroxy-5′-vinyl-phenyl)-5-chlorobenzotriazole (UVAM)was added to 50 grams of the above silicone fluids. After centrifugalmixing, the fluids were placed in the 60° C. oven for 2 to 3 days untilthe UVAM was completely dissolved in the silicone fluids to make “0.25%UVAM silicone fluids.”

Example 2 Preparation of Disc 1

In a vessel, 0.045 grams of platinum-cyclovinylmethylsiloxane complex,was added to 15 grams of the B38 0.25% UVAM silicone fluid. The mixturewas well mixed by high speed centrifugation at least twice for 30seconds. The resulting formed “Part A” of the silicone fluid. The finalcatalyst concentration of three otherwise identical silicone fluids was,by weight, about 0.1%, to about 0.5%. In a separate vessel, “Part B” ofthe silicone fluid was prepared by mixing 0.4038 grams of 25-30%methylhydrosiloxane-dimethylsiloxane copolymer, trimethylsiloxanetermineated, (HMS-301 from Gelest) with 5 grams of the B38, 0.25% UVAMsilicone fluid prepared above. Five grams of Part A and 5 grams of PartB were mixed in a vessel with a theoretical H/V ratio=1.0.

The resulting silicone mixture was poured into a Teflon® mold and themold was placed in an oven at 140° C. for 10 minutes. Moduli of thesediscs (before and after extraction) were measured using a Q800 DMA (TAInstruments). Diameter and thickness of the sample was measured using acalibrator. After loading the sample on the holder, the temperature ofthe system was raised to 35° C. and held at equilibrium for 5 minutesbefore testing. Ramp force was applied to the disk at 1 N/min to themaximum of 9 N/min. The modulus was determined by the slope of twoelongation points (4% and 8%) from the curve. Modulus before extractionwas 40 kPa and after one day static extraction with IPA, the modulus was49 kPa. Refractive indices, measured at 19.5° C. (±1° C.), of the disksbefore and after extraction were 1.434 and 1.433 respectively.

Example 3 Preparation of Disc 2

In another example, In a vessel, 0.045 grams ofplatinum-cyclovinylmethylsiloxane complex, was added to 15 grams of theB38 0.25% UVAM silicone fluid. The mixture was well mixed by high speedcentrifugation at least twice for 30 seconds. In a separate vessel,“Part B” of the silicone fluid was prepared by mixing 0.0908 grams ofphenyltris(dimethylsiloxy)silane and 5 grams of B38 silicone fluid. Fivegrams of Part A and 5 grams of Part B were mixed in a vessel with atheoretical H/V ratio=0.5.

The resulting silicone mixture was poured into a Teflon® mold and themold was placed in an oven at 140° C. for 10 minutes. Moduli of thesediscs (before and after extraction) were measured using a Q800 DMA (TAInstruments). Diameter and thickness of the sample was measured using acalibrator. After loading the sample on the holder, the temperature ofthe system was raised to 35° C. and held at equilibrium for 5 minutesbefore testing. Ramp force was applied to the disk at 1 N/min to themaximum of 9 N/min. The modulus was determined by the slope of twoelongation points (4% and 8%) from the curve. Modulus before extractionwas 18 kPa and after one day static extraction with IPA, the modulus was20 kPa. Refractive indices of the discs before and after extraction were1.435 and 1.433 respectively.

Example 4 Preparation of Disc 3

A silicone fluid with a high refractive index was prepared according tothe following. Part A was prepared by adding 0.045 grams of platinumcyclovinylmethylsiloxane complex to 15 grams of B29 silicone fluid with0.25% UVAM. Part B was prepared by adding 1.0919 grams of hydrideterminated polydimethylsiloxane (DMS-H03 from Gelest) to 15 grams of B29silicone fluid. Five grams of both Part A and Part B were added to avessel and mixed with a theoretical H/V ratio=1.0.

The resulting silicone mixture was poured into a Teflon® mold and themold was placed in an oven at 140° C. for 10 minutes. Moduli of thesediscs (before and after extraction) were measured using a Q800 DMA (TAInstruments). Diameter and thickness of the sample was measured using acalibrator. After loading the sample on the holder, the temperature ofthe system was raised to 35° C. and held at equilibrium for 5 minutesbefore testing. Ramp force was applied to the disk at 1 N/min to themaximum of 9 N/min. The modulus was determined by the slope of twoelongation points (4% and 8%) from the curve. Modulus before extractionwas 47 kPa and after one day static extraction with IPA, the modulus was54 kPa. Two disks of each were also placed in a soxhlet extraction unitand extracted with IPA for an extended period of time. After extractingfor 1, 3, and 5 days, moduli of these samples were 56, 54 and 51 kParespectively. Refractive index of the discs before extraction was 1.466.Refractive index was 1.465 after one and three days of soxhletextraction and 1.464 after 5 days of soxhlet extraction.

Example 5 Preparation of Disc 4

A silicone fluid was prepared according to the following. Part A wasprepared with 0.25% UVAM B49 silicone fluid and 0.1% platinumcyclovinylmethylsiloxane complex. Part B was prepared by adding 0.4294grams of hydride terminated polydimethylsiloxane (DMS-H03 from Gelest)to 10 grams of B49 silicone fluid. Five grams of both Part A and Part Bwere added to a vessel and mixed with a theoretical H/V ratio=1.2.

The resulting silicone mixture was poured into a Teflon® mold and themold was placed in an oven at 140° C. for 10 minutes. Moduli of thesediscs (before and after extraction) were measured using a Q800 DMA (TAInstruments). Diameter and thickness of the sample was measured using acalibrator. After loading the sample on the holder, the temperature ofthe system was raised to 35° C. and held at equilibrium for 5 minutesbefore testing. Ramp force was applied to the disk at 1 N/min to themaximum of 9 N/min. The modulus was determined by the slope of twoelongation points (4% and 8%) from the curve. Modulus before extractionwas 36 kPa and after one day static extraction with IPA, the modulus was44 kPa. Pot life of the fluid was 6 hours. Refractive indices of thediscs before and after static extraction were 1.471 and 1.470respectively.

Example 6 Preparation of Disc 5

A silicone fluid was prepared with high refractive index and highviscosity silicone fluid. Part A was prepared with 0.25% UVAM B49silicone fluid and 0.1% platinum carbonyl cyclovinylmethylsiloxanecomplex. Part B was prepared by adding 0.4294 grams of hydrideterminated polydimethylsiloxane (DMS-H03 from Gelest) to 10 grams of B49silicone fluid. Five grams of both Part A and Part B were added to avessel and mixed with a theoretical H/V ratio=1.2.

The resulting silicone mixture was poured into a Teflon® mold and themold was placed in an oven at 140° C. for 10 minutes. Moduli of thesediscs (before and after extraction) were measured using a Q800 DMA (TAInstruments). Diameter and thickness of the sample was measured using acalibrator. After loading the sample on the holder, the temperature ofthe system was raised to 35° C. and held at equilibrium for 5 minutesbefore testing. Ramp force was applied to the disk at 1 N/min to themaximum of 9 N/min. The modulus was determined by the slope of twoelongation points (4% and 8%) from the curve. Modulus before extractionwas 24 kPa and after one day static extraction with IPA, the modulus was43 kPa. Pot life of the fluid was 20+ hours. The extended pot life wouldprovide flexibility in the manufacturing process.

Example 7 Preparation of Silicone Fluid with Greater than Three but Lessthan Four Vinyl Terminations

This example describes the synthesis of a silicone fluid with an averageof 3.74 vinyl terminations. The silicone fluid is prepared by placing332.03 grams of octaphenylcyclotertasiloxane in a preheated 1000 mLreaction kettle at 105° C. (±10° C.) and stirring. Then, the system ispurged with nitrogen for 30 min. After the system is purged, into thereaction kettle is charged 659.60 grams of octamethylcyclotetrsiloxane,1.75 grams of hexavinyl disiloxane, and 1.80 grams of1,3-divinyltetramethyl disiloxane. Then, 2.73 grams oftetramethylammonium siloxanolate were added to the reaction mixture. Themixture was kept stirring for at least 20 hours at 105° C. (±10° C.).Then, the temperature of the kettle was raised to 150° C. (±20° C.) forat least five hours. The product of the reaction was then allowed tocool to room temperature. After cooling, the silicone fluid was filteredthrough a 0.5μ filter and then wiped dry. The resulting silicone fluidhad an average of 3.74 vinyl terminations and may have a refractiveindex of about 1.47.

Example 8 Preparation of Silicone Fluid with Four Vinyl Terminations

A silicone fluid with the average of 4 vinyl terminated groups may beprepared by charging 332.06 grams of octaphenylcyclotetrasiloxane,659.65 grams of octamethylcyclotetrasiloxane, 2.08 grams of hexavinyldisiloxane, and 1.65 grams of 1,3 divinyltetramethyl disiloxane into areaction kettle. Then 2.50 grams of tetramethylammonium siloxanolate maybe added to the kettle and the reaction mixture may be kept stirring forat least 20 hours at 105° C. (±10° C.). Then, the temperature of kettlemay be raised to 150° C. (±20° C.) for at least 5 hours. After cooling,the silicone fluid may be filtered through 0.5μ filter before wiped-filmprocess. The resulting silicone fluid may have a refractive index ofabout 1.47.

Example 9 Preparation of Silicone Fluid with High Refractive Index

A high refractive index (RI=1.523), high viscosity, hexavinyl terminatedsilicone fluid was prepared as follows. To a 1000 mL preheated reactionkettle was charged 457.03 grams of octaphenylcyclotetrasiloxane at 105°C. (±10° C.). After turning on the mechanical stirrer, the whole systemwas purged with nitrogen for at least 30 minutes. Then, 340.84 grams ofoctamethylcyclotetra-siloxane and 2.15 grams of hexavinyl disiloxanewere added to the kettle. Then, 7.35 grams of tetramethylammoniumsiloxanolate were added initially to the kettle and the reaction mixturewas kept stirring for at least 3 hours at 105° C. (±10° C.). Then, anadditional 2.04 grams of tetramethylammonium siloxanolate were added tothe mixture and the mixture was kept stirring for at least 40 hours at105° C. (±10° C.). The temperature of kettle was raised to 150° C. (±20°C.) for at least 5 hours. After cooling, the silicone fluid was filteredthrough 0.5μ filter before wiped-film process. The viscosity of thisfluid was around 78,000 cp and the refractive index was 1.523.

Example 10 Preparation of Silicone Fluid with a Low Degree ofPolymerization

A hexavinyl terminated silicone fluid was prepared as follows. To a 1000mL preheated reaction kettle was charged 259.77 grams ofoctaphenylcyclotetrasiloxane at 105° C. (±10° C.). After turning on themechanical stirrer, the whole system was purged with nitrogen for atleast 30 minutes. Then, 199.23 grams of octamethylcyclotetra-siloxaneand 46.4 grams of hexavinyl disiloxane were added to the kettle. Then,3.06 grams of tetramethylammonium siloxanolate were added initially tothe kettle and the reaction mixture was kept stirring for at least 3hours at 105° C. (±10° C.). Then, an additional 2.47 grams oftetramethylammonium siloxanolate were added to the mixture, then another1.50 grams, and then the mixture was kept stirring for at least 40 hoursat 105° C. (±10° C.). The temperature of kettle was raised to 150° C.(±20° C.) for at least 5 hours. After cooling, the silicone fluid wasfiltered through 0.5μ filter before wiped-film process. The refractiveindex was 1.52. The sum of x+y+z (equal to the degree of polymerization)was about 22. This silicon fluid can be useful in formulating, forexample, but not limited to, contact lens solutions and hair sprays.

Example 11 Preparation of Silicone Fluid with a Low Degree ofPolymerization

A hexavinyl terminated silicone fluid was prepared as follows. To a 1000mL preheated reaction kettle was charged 250.26 grams ofoctaphenylcyclotetrasiloxane at 105° C. (±10° C.). After turning on themechanical stirrer, the whole system was purged with nitrogen for atleast 30 minutes. Then, 181.87 grams of octamethylcyclotetra-siloxaneand 18.08 grams of hexavinyl disiloxane were added to the kettle. Then,2.70 grams of tetramethylammonium siloxanolate were added to the kettleand the reaction mixture was kept stirring for at least 40 hours at 105°C. (±10° C.). The temperature of kettle was raised to 150° C. (±20° C.)for at least 5 hours. After cooling, the silicone fluid was filteredthrough 0.5μ filter before wiped-film process. The refractive index was1.53. The sum of x+y+z (equal to the degree of polymerization) was equalto about 50. This silicon fluid can be useful in formulating, forexample, but not limited to, contact lens solutions and hair sprays.

Example 12 Preparation of Silicone Fluid with a Medium Degree ofPolymerization

A hexavinyl terminated silicone fluid was prepared as follows. To a 1000mL preheated reaction kettle was charged 109.05 grams ofoctaphenylcyclotetrasiloxane at 105° C. (±10° C.). After turning on themechanical stirrer, the whole system was purged with nitrogen for atleast 30 minutes. Then, 236.05 grams of octamethylcyclotetra-siloxaneand 3.56 grams of hexavinyl disiloxane were added to the kettle. Then,2.00 grams of tetramethylammonium siloxanolate were added to the kettleand the reaction mixture was kept stirring for at least 40 hours at 105°C. (±10° C.). The temperature of kettle was raised to 150° C. (±20° C.)for at least 5 hours. After cooling, the silicone fluid was filteredthrough 0.5μ filter before wiped-film process. The refractive index was1.46. The sum of x+y+z (equal to the degree of polymerization) was equalto about 248. This silicon fluid can be useful in formulating, forexample, but not limited to, topical skin compositions such as skincreams and lotions.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe specification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained. At the veryleast, and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques. Notwithstandingthat the numerical ranges and parameters setting forth the broad scopeare approximations, the numerical values set forth in the specificexamples are reported as precisely as possible. Any numerical value,however, inherently contains certain errors necessarily resulting fromthe standard deviation found in their respective testing measurements.

The terms “a,” “an,” “the” and similar referents used herein (especiallyin the context of the following claims) are to be construed to coverboth the singular and the plural, unless otherwise indicated herein orclearly contradicted by context. Recitation of ranges of values hereinis merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range. Unlessotherwise indicated herein, each individual value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein is intended merely to better illuminate and do not posea limitation on the scope otherwise claimed. No language in thespecification should be construed as indicating that any non-claimedelement is essential to the embodiments disclosed herein.

Groupings of alternative elements or embodiments disclosed herein arenot to be construed as limitations. Each group member may be referred toand claimed individually or in any combination with other members of thegroup or other elements found herein. It is anticipated that one or moremembers of a group may be included in, or deleted from, a group forreasons of convenience and/or patentability. When any such inclusion ordeletion occurs, the specification is deemed to contain the group asmodified thus fulfilling the written description of all Markush groupsused in the appended claims.

Certain embodiments are described herein, including the best mode, ifknown to the inventors at the time of filing. Of course, variations onthese described embodiments will become apparent to those of ordinaryskill in the art upon, reading the foregoing description. The inventorexpects skilled artisans to employ such variations as appropriate.Practice of modifications and equivalents of the subject matter recitedin the claims is expected. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed herein unless otherwise indicated or otherwise clearlycontradicted by context.

Furthermore, references have been made to patents and printedpublications throughout this specification. Each of the above-citedreferences and printed publications individually are incorporated hereinby reference in their entirety.

In closing, it is to be understood that the embodiments disclosed hereinare for illustrative purposes. Other modifications may be employed andare within the scope of the claims. Thus, by way of example, but not oflimitation, alternative configurations may be utilized in accordancewith the teachings herein. Accordingly, the teachings herein are notlimited to that precisely as shown and described.

1. A method of forming an elastomeric article of manufacture comprising;a. providing polymers having a general structure of formula 1, whereinthe polymer comprises at least one pendent vinyl group,

wherein the sum of m and n is x, x ranges from 0 to about 12000, yranges from 0 to about 500, and z ranges from 0 to about 500, the sum ofx, y, and z is at least 1, R¹-R⁸ are each independently CH₃, C₆H₅ orCH═CH₂, if m is greater than zero, at least one of R⁴ or R⁵ must beCH═CH₂, and wherein more than four of R¹, R², R³, R⁶, R⁷, or R⁸ areCH═CH₂; b. providing a cross-linker selected from a nonpolymericcross-linker or a hydride terminated polymeric cross-linker; c.providing a catalyst; d. combining said polymer, said cross-linker andsaid catalyst to form a polymeric mixture; and e. curing said polymericmixture; wherein at least a portion of said elastomeric article ofmanufacture is formed.
 2. The method according to claim 1, wherein saidarticle of manufacture is selected from the group consisting ofintraocular lenses, contact lenses, ocular lenses, body augmentationimplants, medical device coatings and breast implants.
 3. The methodaccording to claim 1, wherein said article of manufacture is capable ofcontrolled release of a therapeutic agent.
 4. The method according toclaim 1, wherein the cross-linker is selected from the group consistingof phenyltris(dimethylsiloxy)silane, 1,1,3,3,-tetraisopropyldisiloxane,1,1,3,3,-tetramethyldisiloxane, 1,1,4,4-tetramethyldisilethane,bis(dimethylsilyl)ethane, 1,1,3,3-tetramethyldisilazane,tetrakis(dimethylsiloxy)silane, hydride-terminatedpolyphony-(dimethylhydrosiloxy)siloxane, hydride terminatedpolydimethylsiloxane, and hydride terminatedmethylhydrosiloxane-phenylmethylsiloxane copolymer.
 5. The methodaccording to claim 1, wherein said polymer is hexavinyl terminated.